Note 6 - Restructuring (Details Textual) - USD ($) $ in Thousands	3 Months Ended
	Apr. 03, 2021	Mar. 28, 2020	Mar. 28, 2020
Restructuring Charges, Total	$ 176	$ 940
Q1 2020 Plan [Member]
Restructuring Charges, Total	0
Restructuring and Related Costs, Incurred Cost, Total		1,100
Restructuring and Related Cost, Cost Incurred to Date	2,000
Q2 2019 Sales Plan [Member]
Restructuring Charges, Total	0		$ (200)
Restructuring and Related Cost, Cost Incurred to Date	2,100
June 2017 Plan [Member]
Restructuring and Related Costs, Incurred Cost, Total	200	$ 100
Restructuring and Related Cost, Cost Incurred to Date	21,200
June 2017 Plan [Member] | Minimum [Member]
Restructuring and Related Cost, Expected Cost, Total	21,500
June 2017 Plan [Member] | Maximum [Member]
Restructuring and Related Cost, Expected Cost, Total	$ 23,500